JP2016161310A - Force detection device and robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a force detection device and a robot which are lightweight and have excellent detection accuracy.SOLUTION: A force detection device according to the present invention has a first member, a second member joined to the first member, and a piezoelectric element joined to the second member, a material constituting the first member differing from a material constituting the second member. It is preferable that the first member is tabular, the piezoelectric element and the second member are arranged at ends of the first member, and a through-hole is preferably formed at center of the first member. It is also preferable that the force detection device has a third member and a fourth member joined to the third member and holding the piezoelectric element together with the second member, a material constituting the third member differing from a material constituting the fourth member.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a force detection device and a robot.

  In recent years, industrial robots have been introduced into production facilities such as factories for the purpose of improving production efficiency. Such an industrial robot includes an arm that can be driven in the direction of one axis or a plurality of axes, and an end effector such as a hand, a component inspection instrument, or a component transfer instrument that is attached to the tip of the arm. Parts manufacturing work such as parts assembly work, parts processing work, parts transport work, parts inspection work, etc. can be executed.

  In such an industrial robot, a force detection device is provided between the arm and the end effector. Since the force detection device is provided at the tip of the arm, the weight of the force detection device occupies a part of the weight that can be transported by the robot (portable weight). For this reason, it is preferable that a force detection apparatus is lightweight.

  In Patent Document 1, a first plate, a second plate disposed at a predetermined interval from the first plate, and opposed to the first plate, and a sensor disposed between the first plate and the second plate. A force detection device comprising an element (piezoelectric element) is described. The first plate has a first pressing portion projecting toward the second plate at a central portion thereof, and the second plate has a second pressing portion projecting toward the first plate at the central portion thereof. The sensor element is sandwiched between the first pressing portion and the second pressing portion. When an external force is applied to at least one of the first plate and the second plate, the sensor element outputs an electric charge according to the external force, thereby detecting the external force. Further, the first plate having the first pressing portion and the second plate having the second pressing portion are integrally formed of stainless steel or the like having a relatively small linear expansion coefficient. For this reason, the influence when the first plate and the second plate are thermally expanded can be reduced, and the detection accuracy of the force detection device can be increased.

JP 2013-130433 A

  However, in the force detection device described in Patent Document 1, each of the first plate and the second plate is entirely made of stainless steel, and stainless steel has a small coefficient of linear expansion, but has a relatively low density. There is a problem that the weight is large.

  Since the detection accuracy of the force detection device must be kept high, simply select a material with a low density as the material constituting the first plate and the material constituting the second plate for weight reduction. I can't.

  An object of the present invention is to provide a force detection device and a robot that are lightweight and have excellent detection accuracy.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1]
A force detection device according to the present invention includes a first member,
A second member coupled to the first member;
A piezoelectric element coupled to the second member,
The material constituting the first member is different from the material constituting the second member.

  As a result, a material different from the material constituting the second member can be freely selected as the material constituting the first member, and similarly, the material constituting the first member as the material constituting the second member. Different materials can be selected freely.

  For example, when the material constituting the first member is a material having a lower density than the material constituting the second member, the weight of the force detection device can be reduced.

  Further, since the thermal expansion of the second member has a greater influence on the deterioration of the detection accuracy of the force detection device than the thermal expansion of the first member, the material constituting the second member is made more than the material constituting the first member. By making the coefficient of linear expansion small, when the force detection device is heated, the amount of deformation due to thermal expansion of the second member can be reduced, and it is possible to suppress unnecessary force from being applied to the piezoelectric element. it can. Thereby, the detection accuracy of the force detection device can be improved.

  Moreover, the strength of the second member can be increased by making the material constituting the second member stronger than the material constituting the first member. When applying pressure to the piezoelectric element, the deformation of the second member can be suppressed. Thereby, the detection accuracy of the force detection device can be improved.

[Application Example 2]
In the force detection device according to the present invention, the first member has a plate shape,
The piezoelectric element and the second member are disposed at an end portion of the first member,
It is preferable that a through hole is formed in the central portion of the first member.

  When the force detection device is heated, the first member is thermally expanded and deformed so that the central portion protrudes, but the deformation amount of the first member can be reduced at the through hole portion, and the piezoelectric element It is possible to suppress unnecessary force from being applied. Thereby, the detection accuracy of the force detection device can be improved.

[Application Example 3]
In the force detection device according to the present invention, a third member;
A fourth member coupled to the third member and sandwiching the piezoelectric element with the second member;
It is preferable that the material constituting the third member is different from the material constituting the fourth member.

  Thereby, a material different from the material constituting the fourth member can be freely selected as the material constituting the third member, and similarly, the material constituting the third member as the material constituting the fourth member. Different materials can be selected freely.

  For example, the weight of the force detection device can be reduced by making the material constituting the third member a material having a lower density than the material constituting the fourth member.

  Further, since the thermal expansion of the fourth member has a greater influence on the deterioration of the detection accuracy of the force detection device than the thermal expansion of the third member, the material constituting the fourth member is made more than the material constituting the third member. By making the coefficient of linear expansion small, when the force detection device is heated, the amount of deformation due to thermal expansion of the fourth member can be reduced, and it is possible to suppress unnecessary force from being applied to the piezoelectric element. it can. Thereby, the detection accuracy of the force detection device can be improved.

  Moreover, the strength of the fourth member can be increased by making the material constituting the fourth member stronger than the material constituting the third member. When applying pressure to the piezoelectric element, the deformation of the fourth member can be suppressed. Thereby, the detection accuracy of the force detection device can be improved.

[Application Example 4]
In the force detection device according to the present invention, the third member has a plate shape,
The piezoelectric element and the fourth member are disposed at an end of the third member,
It is preferable that a through hole is formed in a central portion of the third member.

  When the force detection device is heated, the third member is thermally expanded and deformed so that the central portion protrudes, but the deformation amount of the third member can be reduced at the through hole portion, and the piezoelectric element It is possible to suppress unnecessary force from being applied. Thereby, the detection accuracy of the force detection device can be improved.

[Application Example 5]
In the force detection device according to the present invention, it is preferable that the material constituting the second member is the same as the material constituting the fourth member.

  Thereby, the difference of thermal expansion of the 2nd member and the 4th member can be made small, and it can control that unnecessary force is added to a piezoelectric element.

[Application Example 6]
In the force detection apparatus according to the present invention, it is preferable that the material constituting the first member is the same as the material constituting the third member.

  Thereby, the difference of thermal expansion of the 1st member and the 3rd member can be made small, and it can control that unnecessary force is added to a piezoelectric element.

[Application Example 7]
In the force detection device according to the present invention, it is preferable that the density of the material constituting the third member is smaller than the density of the material constituting the fourth member.
Thereby, weight reduction of a force detection apparatus can be achieved.

[Application Example 8]
In the force detection device according to the present invention, it is preferable that the proof stress of the material constituting the fourth member is larger than the proof stress of the material constituting the third member.

  Thereby, the intensity | strength of a 4th member can be made high and when applying a pressurization to a piezoelectric element via a 4th member with a pressurization volt | bolt, a deformation | transformation of a 4th member can be suppressed. Thereby, the detection accuracy of the force detection device can be improved.

[Application Example 9]
In the force detection device according to the present invention, it is preferable that the linear expansion coefficient of the material forming the fourth member is smaller than the linear expansion coefficient of the material forming the third member.

  Thereby, when a force detection apparatus is heated, the deformation amount by the thermal expansion of a 4th member can be made small, and it can suppress that unnecessary force is added to a piezoelectric element. Thereby, the detection accuracy of the force detection device can be improved.

[Application Example 10]
In the force detection device according to the present invention, it is preferable that the density of the material constituting the first member is smaller than the density of the material constituting the second member.
Thereby, weight reduction of a force detection apparatus can be achieved.

[Application Example 11]
In the force detection device according to the present invention, it is preferable that the proof stress of the material constituting the second member is larger than the proof stress of the material constituting the first member.

  Thereby, the intensity | strength of a 2nd member can be made high and when applying a pressurization to a piezoelectric element via a 2nd member with a pressurization volt | bolt, a deformation | transformation of a 2nd member can be suppressed. Thereby, the detection accuracy of the force detection device can be improved.

[Application Example 12]
In the force detection device according to the present invention, it is preferable that the linear expansion coefficient of the material forming the second member is smaller than the linear expansion coefficient of the material forming the first member.

  Thereby, when a force detection apparatus is heated, the deformation amount by the thermal expansion of a 2nd member can be made small, and it can suppress that unnecessary force is added to a piezoelectric element. Thereby, the detection accuracy of the force detection device can be improved.

[Application Example 13]
A robot according to the present invention includes an arm,
An end effector provided on the arm;
A force detection device that is provided between the arm and the end effector and detects an external force applied to the end effector;
The force detection device includes a first member,
A second member coupled to the first member;
A piezoelectric element coupled to the second member,
The material constituting the first member is different from the material constituting the second member.

  As a result, a material different from the material constituting the second member can be freely selected as the material constituting the first member, and similarly, the material constituting the first member as the material constituting the second member. Different materials can be selected freely.

  For example, when the material constituting the first member is a material having a lower density than the material constituting the second member, the weight of the force detection device can be reduced.

  Further, since the thermal expansion of the second member has a greater influence on the deterioration of the detection accuracy of the force detection device than the thermal expansion of the first member, the material constituting the second member is made more than the material constituting the first member. By making the coefficient of linear expansion small, when the force detection device is heated, the amount of deformation due to thermal expansion of the second member can be reduced, and it is possible to suppress unnecessary force from being applied to the piezoelectric element. it can. Thereby, the detection accuracy of the force detection device can be improved.

  Moreover, the strength of the second member can be increased by making the material constituting the second member stronger than the material constituting the first member. When applying pressure to the piezoelectric element, the deformation of the second member can be suppressed. Thereby, the detection accuracy of the force detection device can be improved.

It is sectional drawing which shows embodiment of the force detection apparatus of this invention. It is sectional drawing of the force detection apparatus shown in FIG. It is sectional drawing which shows schematically the electric charge output element of the force detection apparatus shown in FIG. It is a figure which shows typically the state by which the force detection apparatus shown in FIG. 1 was heated. In the force detection apparatus shown in FIG. 1, it is a figure which shows typically the state by which the thing in which the through-hole was not formed in the 1st member of a 1st base and the 3rd member of a 2nd base was heated. It is a figure which shows an example of the single arm robot using the force detection apparatus of this invention. It is a figure which shows an example of the multi-arm robot using the force detection apparatus of this invention.

  Hereinafter, a force detection device and a robot of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

<Embodiment of Force Detection Device>
FIG. 1 is a cross-sectional view showing an embodiment of the force detection device of the present invention. FIG. 2 is a cross-sectional view of the force detection device shown in FIG. FIG. 3 is a cross-sectional view schematically showing the charge output element of the force detection device shown in FIG. FIG. 4 is a diagram schematically showing a state in which the force detection device shown in FIG. 1 is heated. FIG. 5 is a diagram schematically showing a state in which the first member of the first base and the third member of the second base in which no through hole is formed are heated in the force detection device shown in FIG. .

  In the following, the upper side in FIG. 1 is referred to as “upper” or “upper”, and the lower side is referred to as “lower” or “lower”.

  FIG. 2 shows an α axis, a β axis, and a γ axis as three axes orthogonal to each other. 1 and 3 show only the γ-axis among the three axes. The direction parallel to the α (A) axis is “α (A) axis direction” or “α direction”, and the direction parallel to the β (B) axis is “β (B) axis direction” or “β direction”, γ ( C) A direction parallel to the axis is referred to as “γ (C) axis direction” or “γ direction”. A plane defined by the α axis and the β axis is referred to as an “αβ plane”, a plane defined by the β axis and the γ axis is referred to as a “βγ plane”, and a plane defined by the α axis and the γ axis is referred to as “ It is called “αγ plane”. In the α direction, β direction, and γ direction, the arrow tip side is defined as “+ (positive) side” and the arrow base end side is defined as “− (negative) side”.

  The force detection device 1 shown in FIG. 1 has an external force applied to the force detection device 1, that is, a six-axis force (a translational force component in the α, β, and γ axis directions and a rotational force component around the α, β, and γ axes). It has a function to detect.

  The force detection device 1 includes a first base 2, a second base 3 disposed at a predetermined interval from the first base 2, and facing the first base 2, and the first base 2 and the second base 3. A side wall 16 provided on the outer periphery, four analog circuit boards 4 housed (provided) between the first base 2 and the second base 3, the first base 2 and the second base 3, Between each of the analog circuit boards 4 and one digital circuit board 5 that is electrically connected to each analog circuit board 4 and mounted on each analog circuit board 4 and a signal (charge) according to the external force received. Output sensor (piezoelectric element) 10 that is an element that outputs a voltage, and four sensor devices (pressure detectors) 6 having a package (accommodating part) 60 that accommodates the charge output elements 10, and eight pressurizing bolts (fixing members) 71).

Below, the structure of each part of the force detection apparatus 1 is explained in full detail.
In the following description, as shown in FIG. 2, among the four sensor devices 6, the sensor device 6 located on the right side in FIG. 2 is referred to as “sensor device 6 </ b> A”, and hereinafter “sensor” in order counterclockwise. These are referred to as “device 6B”, “sensor device 6C”, and “sensor device 6D”. When the sensor devices 6A, 6B, 6C, and 6D are not distinguished, they are referred to as “sensor device 6”.

  As shown in FIG. 1, the first base (base plate) 2 is provided on the upper surface of the plate-shaped first member (bottom plate) 22 and the end of the first member 22, and protrudes upward from the upper surface. And four second members (wall portions) 24. The planar shape (the shape seen from the thickness direction) of the first member 22 (first base 2) is circular. Note that the planar shape of the first member 22 is not limited to the illustrated shape, and examples thereof include a quadrangle such as a square and a rectangle, a polygon such as a pentagon and a hexagon, and an ellipse.

  For example, when the force detection device 1 is provided between a robot arm and an end effector and is used as a force sensor for detecting an external force applied to the end effector, the lower surface 221 of the first base 2 is It functions as an attachment surface (first attachment surface) for the arm (object).

  Each second member 24 is fixed (coupled) to the first member 22. Although the fixing method is not particularly limited, in the illustrated configuration, each second member 24 is fixed to the first member 22 by a plurality of screws 172.

  In addition, convex portions 23 are formed to project from the surfaces of the second members 24 facing outward. The top surface (first surface) 231 of each convex portion 23 is a plane perpendicular to the first member 22. Each of the second members 24 is provided with two female screws 241 that are screwed into pressurizing bolts 71 described later (see FIG. 2).

  As shown in FIG. 1, a second base (cover plate) 3 is arranged so as to face the first base 2 with a predetermined interval.

  The second base 3 is provided with a plate-like third member (top plate) 32 and four fourth members (wall portions) that are provided on the lower surface of the end of the third member 32 and project downward from the lower surface. 33). The planar shape of the third member 32 (second base 3) is not particularly limited, but is preferably a shape corresponding to the planar shape of the first member 22 (first base 2). The planar shape of the member 32 is circular like the planar shape of the first member 22. The third member 32 is preferably the same size as the first member 22 or a size that includes the first member 22.

  Taking the case where the force detection device 1 is used as a force sensor for the robot as an example, the upper surface (second surface) 321 of the second base 3 is attached to an end effector (object) attached to the arm of the robot. It functions as a surface (second mounting surface). Further, the upper surface 321 of the second base 3 and the lower surface 221 of the first base 2 described above are parallel in a natural state where no external force is applied.

  Each fourth member 33 is fixed (coupled) to the third member 32. Although the fixing method is not particularly limited, in the illustrated configuration, each fourth member 33 is fixed to the third member 32 with a plurality of screws 173.

  The inner wall surface (second surface) 331 of each fourth member 33 is a plane perpendicular to the third member 32. The sensor device 6 is provided between the top surface 231 of each second member 24 and the inner wall surface 331 of each fourth member 33.

  The first base 2 and the second base 3 are connected and fixed by eight pressurizing bolts 71. That is, each second member 24 and each fourth member 33 are connected and fixed by the two pressurizing bolts 71, respectively. As shown in FIG. 2, there are eight (a plurality) of the pressurizing bolts 71, and two of them are arranged on both sides of each sensor device 6. The number of pressurizing bolts 71 for one sensor device 6 is not limited to two, and may be three or more, for example.

  Moreover, it does not specifically limit as a constituent material of the pressurization volt | bolt 71, For example, various resin materials, various metal materials, etc. can be used.

  Thus, the first base 2 and the second base 3 connected by the pressurizing bolt 71 form a storage space for storing the sensor devices 6A to 6D, the analog circuit board 4, and the digital circuit board 5. The storage space has, for example, a circular or rounded square cross-sectional shape.

  Further, as shown in FIGS. 1 and 2, side wall portions 16 are provided on the outer peripheral portions of the first base portion 2 and the second base portion 3. Thereby, in the outer peripheral part of the 1st base 2 and the 2nd base 3, the space between the 1st base 2 and the 2nd base 3 can be sealed, The 1st base 2 and the 2nd base 3 It is possible to prevent dust and dust from entering the space between the two.

  The side wall portion 16 includes a tubular portion 161 that forms a tubular shape, and a flange 162 that is formed on the inner peripheral side surface of the proximal end portion (lower end portion) of the tubular portion 161. The inner shape and the outer shape of the cylindrical portion 161 when viewed from the thickness direction of the first base 2 and the second base 3 are shapes corresponding to the planar shapes of the first base 2 and the second base 3, respectively. Yes, in the configuration shown, it is circular.

  The side wall portion 16 has a base end portion, that is, a flange 162 fixed to the first base portion 2. Although the fixing method is not particularly limited, in the illustrated configuration, the flange 162 is fixed to the first member 22 of the first base 2 with a plurality of screws 171.

  As shown in FIG. 1, an analog circuit board 4 that is electrically connected to the sensor device 6 is provided between the first base 2 and the second base 3.

  In the portion of the analog circuit board 4 where the sensor device 6 (specifically, the charge output element 10) is disposed, a hole 41 into which each convex portion 23 of the first base 2 is inserted is formed. The hole 41 is a through hole that penetrates the analog circuit board 4.

  Further, as shown in FIG. 2, the analog circuit board 4 is provided with a through hole through which each pressurizing bolt 71 passes, and a portion (through hole) of the analog circuit board 4 through which the pressurizing bolt 71 passes is provided. A pipe 43 made of an insulating material such as a resin material is fixed by fitting, for example.

  Further, as shown in FIG. 1, each analog circuit is located between the first base 2 and the second base 3 at a position different from the position where each analog circuit board 4 is provided on the first base 2. A digital circuit board 5 electrically connected to the board 4 is provided. The digital circuit board 5 is arranged to be parallel to the first member 22 of the first base 2 and the third member 32 of the second base 3. The position in the thickness direction of the first base portion 2 and the second base portion 3 of the digital circuit board 5 is not particularly limited as long as it is between the first base portion 2 and the second base portion 3. For example, as shown in FIG. Thus, it may be in the vicinity of the first base 2, in the vicinity of the second base 3, or in the middle position (central part) between the first base 2 and the second base 3. The digital circuit board 5 is fixed to the first member 22. Although the fixing method is not particularly limited, in the illustrated configuration, the digital circuit board 5 is fixed to the first member 22 with a plurality of screws 174.

  The components of the first base 2, the second base 3, and the analog circuit board 4 other than the elements and the wirings, the components of the digital circuit board 5 and the parts other than the wirings, For example, various resin materials and various metal materials can be used.

  Here, as described above, in the first base 2, the first member 22 and the second member 24 are configured as separate members, and similarly, in the second base 3, the third member 32 and the fourth member 33. It is comprised with another member. The material constituting the first member 22 and the material constituting the second member 24 are different. Similarly, the material constituting the third member 32 and the material constituting the fourth member 33 are different. Is different.

  Hereinafter, the density, yield strength, and linear expansion coefficient of the first member 22, the third member 32, the second member 24, and the fourth member 33 will be described.

  The proof stress of the material which comprises the 2nd member 24 and the 4th member 33 is respectively so preferable that it is large, Specifically, it is preferable that it is 800 Mpa or more, It is more preferable that it is 900 Mpa or more, 900 Mpa or more, 2000 Mpa or less More preferably. This proof stress is measured in accordance with “JISZ2241 (metal material tensile test method)”.

  By setting the proof stress large, the strength of the second member 24 and the fourth member 33 can be increased, and the second member 24 and the fourth member 33 are connected and fixed by the pressurizing bolt 71 to output the charge. When pressure is applied to the element 10, deformation of the second member 24 and the fourth member 33 can be suppressed. Thereby, the detection accuracy of the force detection device 1 can be improved.

  However, if the yield strength is smaller than the lower limit value, the strength of the second member 24 and the fourth member 33 may be insufficient depending on other conditions.

Further, the density of the material constituting the second member 24 and the fourth member 33 is preferably as small as possible. However, considering that the proof stress is set to a value within the preferred range, it is 10 g / cm ³ or less. It is preferably 8 g / cm ³ or less, more preferably 5 g / cm ³ or more and 8 g / cm ³ or less.

  Since the volume of the second member 24 and the fourth member 33 is smaller than that of the first member 22 and the third member 32, there is almost no effect in reducing the weight even if the material density is relatively large. If the density is larger than the upper limit, the weight may not be reduced depending on other conditions.

Further, the linear expansion coefficients of the materials constituting the second member 24 and the fourth member 33 are preferably as small as possible. However, considering that the proof stress is set to a value within the preferable range, 20 × 10 ^−6. / K or less, preferably 15 × 10 ⁻⁶ / K or less, more preferably 5 × 10 ⁻⁶ / K or more and 15 × 10 ⁻⁶ / K or less.

  By setting the linear expansion coefficient to be small, when the force detection device 1 is heated, the deformation amount due to the thermal expansion of the second member 24 and the fourth member 33 can be reduced, which is unnecessary for the charge output element 10. It can suppress that force is added. Thereby, the detection accuracy of the force detection device 1 can be improved.

  However, if the linear expansion coefficient is larger than the upper limit value, the detection accuracy of the force detection device 1 may be lowered depending on other conditions.

In addition, the density of the material constituting the first member 22 and the third member 32 is preferably as small as possible. Specifically, the density is preferably 6 g / cm ³ or less, and preferably 4 g / cm ³ or less. More preferably, it is more preferably 0.5 g / cm ³ or more and 4 g / cm ³ or less.

  By setting the density small, the weight can be reduced. Moreover, since the volume of the 1st member 22 and the 3rd member 32 is larger than the 2nd member 24 and the 4th member 33, weight reduction can be achieved significantly.

  However, if the density is larger than the upper limit value, there is a possibility that the weight cannot be reduced depending on other conditions.

  Moreover, the proof stress of the material which comprises the 1st member 22 and the 3rd member 32 is respectively so preferable that it is large, but when considering setting a density to the value within the said suitable range, it is preferable that it is 200 Mpa or more. 400 Mpa or more, more preferably 400 Mpa or more and 900 Mpa or less.

  Since the first member 22 and the third member 32 are not portions fixed by the pressurizing bolt 71, there is almost no problem even if the proof stress of the material is relatively small. However, if the proof strength is smaller than the lower limit value, Depending on other conditions, the strength may be insufficient.

Further, the linear expansion coefficients of the materials constituting the first member 22 and the third member 32 are preferably as small as possible. However, in consideration of setting the density to a value within the preferred range, 30 × 10 ^−6. / is preferably K or less, more preferably at most ^{26 × 10 -6 / K, 15} × 10 -6 / K or more, and more preferably not more than 26 × ^{10 -6} / K.

  Since the first member 22 and the third member 32 are not in contact with the sensor device 6, the thermal expansion is less affected than the second member 24 and the fourth member 33, but the linear expansion coefficient is higher than the upper limit value. If it is too large, the detection accuracy of the force detection device 1 may decrease depending on other conditions.

  Moreover, it is preferable that the proof stress of the material which comprises the 2nd member 24 and the 4th member 33 is larger than the proof stress of the material which comprises the 1st member 22 and the 3rd member 32, respectively.

  Further, when the proof stress of the material constituting the first member 22 and the third member 32 is A1, and the proof stress of the material constituting the second member 24 and the fourth member 33 is A2, the ratio A2 / A1 of A2 and A1. Is preferably 1.2 or more, more preferably 1.2 or more and 10 or less, and still more preferably 1.8 or more and 5 or less.

  Thereby, the strength of the second member 24 and the fourth member 33 can be made higher than that of the first member 22 and the third member 32, and the second member 24 and the fourth member 33 are connected by the pressurizing bolt 71. When the pressure is applied to the charge output element 10 while being fixed, deformation of the second member 24 and the fourth member 33 can be suppressed. Thereby, the detection accuracy of the force detection device 1 can be improved.

  However, if A2 / A1 is smaller than the lower limit, the strength of the second member 24 and the fourth member 33 may be insufficient depending on other conditions.

  Moreover, it is preferable that the density of the material which comprises the 1st member 22 and the 3rd member 32 is smaller than the density of the material which comprises the 2nd member 24 and the 4th member 33, respectively.

  Further, when the density of the material constituting the first member 22 and the third member 32 is B1, and the density of the material constituting the second member 24 and the fourth member 33 is B2, the ratio B1 / B2 between B1 and B2 Is preferably 0.7 or less, more preferably 0.1 or more and 0.7 or less, and further preferably 0.1 or more and 0.4 or less.

  Since the volume of the first member 22 and the third member 32 is larger than that of the second member 24 and the fourth member 33, the weight can be reduced.

  However, if B1 / B2 is larger than the upper limit value, the weight may not be reduced depending on other conditions.

  Moreover, it is preferable that the linear expansion coefficient of the material which comprises the 2nd member 24 and the 4th member 33 is smaller than the linear expansion coefficient of the material which comprises the 1st member 22 and the 3rd member 32, respectively.

  Specifically, when the linear expansion coefficient of the material constituting the first member 22 and the third member 32 is C1, and the linear expansion coefficient of the material constituting the second member 24 and the fourth member 33 is C2, C2 The ratio C2 / C1 with C1 is preferably 0.6 or less, more preferably 0.1 or more and 0.6 or less, and further preferably 0.1 or more and 0.5 or less. .

  Thereby, when the force detection apparatus 1 is heated, the deformation amount due to thermal expansion of the second member 24 and the fourth member 33 which are members in contact with the sensor device 6 can be reduced, and the charge output element 10 can be reduced. It is possible to suppress unnecessary force from being applied. Thereby, the detection accuracy of the force detection device 1 can be improved.

  However, if C2 / C1 is larger than the upper limit value, the detection accuracy of the force detection device 1 may be lowered depending on other conditions.

  Moreover, as a material which comprises the 1st member 22 and the 3rd member 32, what has the above characteristics is respectively preferable, for example, A7075-T6 (made by Toho Nonferrous Metals), A7075-T651 (Toho) Examples thereof include aluminum alloys such as Nonferrous Metal Co., Ltd., titanium alloys such as DAT51 (Daido Special Steel Co., Ltd.), and magnesium alloys such as AZ91 (Sumitomo Electric Industries, Ltd.). Of these, aluminum alloys such as A7075-T6 and A7075-T651 are preferable.

The densities of A7075-T6 and A7075-T651 are 2.7 g / cm ³ , the yield strength is 505 Mpa, and the linear expansion coefficient is 24 × 10 ⁻⁶ / K. The density of DAT51 is 4.69 g / cm ³ , the proof stress is 825 Mpa, and the linear expansion coefficient is 8 × 10 ⁻⁶ / K. The density of AZ91 is 1.8 g / cm ³ , the yield strength is 280 Mpa, and the linear expansion coefficient is 27.2 × 10 ⁻⁶ / K.

  Moreover, as a material which comprises the 2nd member 24 and the 4th member 33, what has the above characteristics is respectively preferable, For example, alloy steels, such as NAK55 (made by Daido Special Steel Co., Ltd.), etc. are mentioned. .

The density of NAK55 is 7.8 g / cm ³ , the proof stress is 1000 Mpa, and the linear expansion coefficient is 11.3 × 10 ⁻⁶ / K.

  Further, the material constituting the first member 22 and the material constituting the third member 32 may be the same or different, but are preferably the same. By using the same material, the difference in thermal expansion between the first member 22 and the third member 32 can be reduced, and an unnecessary force applied to the charge output element 10 can be suppressed.

  Similarly, the material constituting the second member 24 and the material constituting the fourth member 33 may be the same or different, but are preferably the same. By using the same material, the difference in thermal expansion between the second member 24 and the fourth member 33 can be reduced, and an unnecessary force can be prevented from being applied to the charge output element 10.

  Further, a through hole 20 is formed in the central portion of the first member 22 of the first base portion 2, and similarly, a through hole 30 is formed in the central portion of the third member 32 of the second base portion 3. Similarly, a through hole 50 is formed in the center of the digital circuit board 5.

  As shown in FIG. 5, when the through holes 20 and 30 are not formed in the first member 22 of the first base 2 and the third member 32 of the second base 3, when the force detection device 1 is heated, The first member 22 and the third member 32 are thermally expanded and warped so that the center portions of the first member 22 and the third member 32 are separated from each other. This is because the second member 24 and the fourth member 33 are provided at the end portions of the first member 22 and the third member 32, so that the strength is lower in the central portion than in the end portion. Because.

  On the other hand, as shown in FIG. 4, if the through holes 20 and 30 are formed in the first member 22 of the first base 2 and the third member 32 of the second base 3, the first member 22 and the third member When the member 32 warps due to thermal expansion, the deformation amount of the first member 22 can be reduced in the portion of the through hole 20, and similarly, the deformation amount of the third member 32 is reduced in the portion of the through hole 30. be able to. Further, the warp of the first member 22 is reduced by the through hole 20, and similarly, the warp of the third member 32 is reduced by the through hole 30. Thereby, it can suppress that unnecessary force is added to the charge output element 10, and the detection accuracy of the force detection apparatus 1 can be improved.

  The through holes 20, 30, and 50 are arranged at the same position as seen from the thickness direction of the first member 22, the third member 32, and the digital circuit board 5. In addition, the position of each through-hole 20, 30, and 50 is not restricted to this, You may be arrange | positioned in a different position.

  Moreover, the planar shape (shape seen from the thickness direction) of each through-hole 20, 30, and 50 is each quadrangular. In addition, the planar shape of each through-hole 20, 30, and 50 is not limited to what is illustrated, For example, other polygons, such as a pentagon and a hexagon, circle, an ellipse, etc. are mentioned.

  Moreover, the planar shape of each through-hole 20, 30, and 50 may be the same, and may differ.

  In addition, although the 1st base 2 and the 2nd base 3 are each comprised by the member which makes plate shape, it is not limited to this, For example, one base part is comprised by the member which makes plate shape, and the other The base may be composed of a block-shaped member.

Next, the sensor device 6 will be described.
[Sensor device]
As shown in FIGS. 1 and 2, the sensor device 6 </ b> A includes a top surface 231 of one convex portion 23 among the four convex portions 23 of the first base 2, and an inner wall surface 331 facing the top surface 231. It is pinched by. Similar to the sensor device 6A, the sensor device 6B is sandwiched between the top surface 231 of one convex portion 23 different from the above and the inner wall surface 331 facing the top surface 231. Further, the sensor device 6C is sandwiched between the top surface 231 of one convex portion 23 different from the above and the inner wall surface 331 facing the top surface 231. Further, the sensor device 6D is sandwiched between the top surface 231 of one convex portion 23 different from the above and the inner wall surface 331 facing the top surface 231. It can also be said that the charge output elements 10 of the sensor devices 6A, 6B, 6C, and 6D are coupled to the second member 24 and the fourth member 33, respectively.

  Hereinafter, the direction in which the sensor devices 6A to 6D are sandwiched between the first base portion 2 and the second base portion 3 is referred to as “a sandwiching direction SD”. Further, among the sensor devices 6A to 6D, the direction in which the sensor device 6A is clamped is the first clamping direction, the direction in which the sensor device 6B is clamped is the second clamping direction, and the direction in which the sensor device 6C is clamped. The third clamping direction and the direction in which the sensor device 6D is clamped may be referred to as a fourth clamping direction.

  In this embodiment, as shown in FIG. 1, the sensor device 6 is provided on the second base 3 (fourth member 33) side of the analog circuit board 4, but the sensor device 6 is an analog circuit board. 4 may be provided on the first base 2 side.

  As shown in FIG. 2, the sensor device 6 </ b> A and the sensor device 6 </ b> B and the sensor device 6 </ b> C and the sensor device 6 </ b> D are disposed symmetrically with respect to the central axis 271 along the β axis of the first base 2. That is, the sensor devices 6 </ b> A to 6 </ b> D are arranged at equiangular intervals around the center 272 of the first base 2. By arranging the sensor devices 6A to 6D in this way, it is possible to detect the external force without bias.

  The arrangement of the sensor devices 6A to 6D is not limited to that shown in the drawing, but the sensor devices 6A to 6D are as far as possible from the center (center 272) of the second base 3 when viewed from the upper surface 321 of the second base 3. It is preferable that they are arranged at spaced positions. Thereby, the external force applied to the force detection apparatus 1 can be detected stably.

  As shown in FIG. 1, the sensor device 6 arranged in this manner includes a charge output element 10 and a package 60 that houses the charge output element 10. In the present embodiment, the sensor devices 6A to 6D have the same configuration. Note that the package may be omitted.

Hereinafter, the charge output element 10 provided in the sensor device 6 will be described.
[Charge output element]
The charge output element 10 has a function of outputting a charge according to an external force applied to the force detection device 1, that is, an external force applied to at least one base of the first base 2 or the second base 3.

  In addition, since each charge output element 10 with which the sensor devices 6A-6D are provided has the same configuration, one charge output element 10 will be mainly described.

  As shown in FIG. 3, the charge output element 10 included in the sensor device 6 includes a ground electrode layer 11, a first sensor 12, a second sensor 13, and a third sensor 14.

  The first sensor 12 has a function of outputting a charge Qx according to an external force (shearing force). The second sensor 13 has a function of outputting a charge Qz according to an external force (compression / tensile force). The third sensor 14 outputs a charge Qy according to an external force (shearing force).

  In the charge output element 10 included in the sensor device 6, the ground electrode layer 11 and the sensors 12, 13, and 14 are alternately stacked in parallel. Hereinafter, this stacked direction is referred to as “stacked direction LD”. The stacking direction LD is perpendicular to the normal line NL2 of the upper surface 321 (or the normal line NL1 of the lower surface 221). The stacking direction LD is parallel to the sandwiching direction SD.

  In addition, the shape of the charge output element 10 is not particularly limited, but in the present embodiment, the charge output element 10 has a quadrangular shape when viewed from the direction perpendicular to the inner wall surface 331 of each fourth member 33. In addition, as another external shape of each electric charge output element 10, other polygons, such as a pentagon, circle, an ellipse, etc. are mentioned, for example.

  Hereinafter, the ground electrode layer 11, the first sensor 12, the second sensor 13, and the third sensor 14 will be described.

  The ground electrode layer 11 is an electrode grounded to the ground (reference potential point). Although the material which comprises the ground electrode layer 11 is not specifically limited, For example, gold | metal | money, titanium, aluminum, copper, iron, or an alloy containing these is preferable. Among these, it is particularly preferable to use stainless steel which is an iron alloy. The ground electrode layer 11 made of stainless steel has excellent durability and corrosion resistance.

  The first sensor 12 is in response to an external force (shearing force) in the first detection direction orthogonal to the stacking direction LD (first clamping direction), that is, in the same direction as the direction of the normal line NL2 (normal line NL1). It has a function of outputting charge Qx. That is, the first sensor 12 is configured to output a positive charge or a negative charge according to an external force. Note that an x-axis direction in a first piezoelectric layer 121 and a second piezoelectric layer 123 described later is the first detection direction.

  The first sensor 12 includes a first piezoelectric layer (a first detection plate (first substrate)) 121 and a second piezoelectric layer (a first piezoelectric layer 121 provided to face the first piezoelectric layer 121). A detection plate (first substrate) 123, and an output electrode layer 122 provided between the first piezoelectric layer 121 and the second piezoelectric layer 123.

  The first piezoelectric layer 121 is composed of a Y-cut quartz plate and has an x-axis, a y-axis, and a z-axis that are crystal axes orthogonal to each other. The y-axis is an axis along the thickness direction of the first piezoelectric layer 121, the x-axis is an axis along the depth direction in FIG. 3, and the z-axis is the vertical direction in FIG. Axis along.

  In the following description, it is assumed that the tip side of each of the illustrated arrows is “+ (positive)” and the base end side is “− (negative)”. A direction parallel to the x axis is referred to as an “x axis direction”, a direction parallel to the y axis is referred to as a “y axis direction”, and a direction parallel to the z axis is referred to as a “z axis direction”. The same applies to a second piezoelectric layer 123, a third piezoelectric layer 131, a fourth piezoelectric layer 133, a fifth piezoelectric layer 141, and a sixth piezoelectric layer 143 described later.

  The second piezoelectric layer 123 is also composed of a Y-cut quartz plate and has an x-axis, a y-axis, and a z-axis that are crystal axes orthogonal to each other. The y-axis is an axis along the thickness direction of the second piezoelectric layer 123, the x-axis is an axis along the depth direction in FIG. 3, and the z-axis is the vertical direction in FIG. Axis along.

  The output electrode layer 122 has a function of outputting positive charges or negative charges generated in the first piezoelectric layer 121 and the second piezoelectric layer 123 as charges Qx.

  The second sensor 13 has a function of outputting a charge Qz according to an external force (compression / tensile force). That is, the second sensor 13 is configured to output a positive charge according to the compressive force and output a negative charge according to the tensile force. Note that the x-axis direction in a third piezoelectric layer 131 and a fourth piezoelectric layer 133, which will be described later, is the direction of the compression and tensile force detected.

  The second sensor 13 includes a third piezoelectric layer (third substrate) 131, a fourth piezoelectric layer (third substrate) 133 provided to face the third piezoelectric layer 131, The output electrode layer 132 is provided between the third piezoelectric layer 131 and the fourth piezoelectric layer 133.

  The third piezoelectric layer 131 is composed of an X-cut quartz plate and has an x axis, a y axis, and a z axis that are orthogonal to each other. The x-axis is an axis along the thickness direction of the third piezoelectric layer 131, the y-axis is an axis along the vertical direction in FIG. 3, and the z-axis is the depth direction in the drawing of FIG. Axis along.

  The fourth piezoelectric layer 133 is also composed of an X-cut quartz plate and has an x-axis, a y-axis, and a z-axis that are orthogonal to each other. The x-axis is an axis along the thickness direction of the fourth piezoelectric layer 133, the y-axis is an axis along the vertical direction in FIG. 3, and the z-axis is a depth direction in the drawing of FIG. Axis along.

  The output electrode layer 132 has a function of outputting positive charges or negative charges generated in the third piezoelectric layer 131 and the fourth piezoelectric layer 133 as charges Qz.

  The third sensor 14 is orthogonal to the stacking direction LD (second clamping direction), and has a second detection direction that intersects the first detection direction of the external force that acts when the first sensor 12 outputs the charge Qx. It has a function of outputting a charge Qx according to an external force (shearing force). That is, the third sensor 14 is configured to output a positive charge or a negative charge according to an external force. Note that an x-axis direction in a fifth piezoelectric layer 141 and a sixth piezoelectric layer 143 described later is the second detection direction.

  The third sensor 14 includes a fifth piezoelectric layer (second detection plate (second substrate)) 141 and a sixth piezoelectric layer (second layer) provided to face the fifth piezoelectric layer 141. A detection plate (second substrate) 143, and an output electrode layer 142 provided between the fifth piezoelectric layer 141 and the sixth piezoelectric layer 143.

  The fifth piezoelectric layer 141 is composed of a Y-cut quartz plate and has an x-axis, a y-axis, and a z-axis that are crystal axes orthogonal to each other. The y-axis is an axis along the thickness direction of the fifth piezoelectric layer 141, the x-axis is an axis along the vertical direction in FIG. 3, and the z-axis is a depth direction in the drawing of FIG. Axis along.

  The sixth piezoelectric layer 143 is also composed of a Y-cut quartz plate and has an x axis, a y axis, and a z axis, which are crystal axes orthogonal to each other. The y-axis is an axis along the thickness direction of the sixth piezoelectric layer 143, the x-axis is an axis along the vertical direction in FIG. 3, and the z-axis is the depth direction in the drawing of FIG. Axis along.

  In the charge output element 10, the x-axis of the first piezoelectric layer 121 and the second piezoelectric layer 123, and the fifth piezoelectric layer 141 and the sixth piezoelectric layer 143 when viewed from the stacking direction LD. The x-axis of each intersects. Further, when viewed from the stacking direction LD, each z axis of the first piezoelectric layer 121 and the second piezoelectric layer 123, and each z axis of the fifth piezoelectric layer 141 and the sixth piezoelectric layer 143. And intersect.

  The output electrode layer 142 has a function of outputting positive charges or negative charges generated in the fifth piezoelectric layer 141 and the sixth piezoelectric layer 143 as charges Qy.

  As described above, in the charge output element 10, the first sensor 12, the second sensor 13, and the third sensor 14 are stacked so that the force detection directions of the sensors are orthogonal to each other. Thereby, each sensor can induce an electric charge according to force components orthogonal to each other. Therefore, the charge output element 10 can output three charges Qx, Qy, and Qz according to each external force along the x axis, the y axis, and the z axis.

  Further, as described above, the charge output element 10 can output the charge Qz, but the force detection device 1 preferably does not use the charge Qz when obtaining each external force. That is, the force detection device 1 is preferably used as a device that detects a shearing force without detecting compression or tensile force. Thereby, the noise component resulting from the temperature change of the force detection apparatus 1 can be reduced. The charge Qz is used, for example, for adjusting the pressurization by the pressurization bolt 71 even when not being used when obtaining each external force.

In the present embodiment, the piezoelectric layers described above (the first piezoelectric layer 121, the second piezoelectric layer 123, the third piezoelectric layer 131, the fourth piezoelectric layer 133, and the fifth piezoelectric layer). The body layer 141 and the sixth piezoelectric layer 143) are all configured using quartz, but each piezoelectric layer may be configured using a piezoelectric material other than quartz. Examples of piezoelectric materials other than quartz include topaz, barium titanate, lead titanate, lead zirconate titanate (PZT: Pb (Zr, Ti) O ₃ ), lithium niobate, lithium tantalate, and the like. However, each piezoelectric layer preferably has a configuration using quartz. This is because the piezoelectric layer made of quartz has excellent characteristics such as a wide dynamic range, high rigidity, high natural frequency, and high load resistance.

  In the present embodiment, the number of piezoelectric layers of the first sensor 12, the second sensor 13, and the third sensor 14 is two, but is not limited to this, for example, one. Also good.

  As described above, the first base 2 and the second base 3 are fixed by the pressurizing bolt 71.

  The fixing with the pressurizing bolt 71 is performed by attaching the pressurizing bolt 71 from the fourth member 33 side of the second base 3 to the first base 2 in a state where the sensor devices 6 are arranged between the top surface 231 and the inner wall 331. The male screw (not shown) of the pressurizing bolt 71 is screwed into the female screw 241 formed on the second member 24. In this manner, the charge output element 10 has a predetermined pressure by the first base 2 and the second base 3, that is, the second member 24 and the fourth member 33, together with the package 60 that houses the charge output element 10. That is, a pressurized pressure is applied.

  Each second member 24 and each fourth member 33 are fixed by two pressurizing bolts 71 so that a predetermined amount of displacement (movement) is possible. Since the second member 24 and the fourth member 33 are fixed so that a predetermined amount of displacement is possible, an external force (shearing force) is applied to the force detection device 1 so that a shearing force acts on the charge output element 10. Then, a frictional force between the layers constituting the charge output element 10 is surely generated, so that the charge can be reliably detected. Further, the pressurizing direction by each pressurizing bolt 71 is a direction parallel to the stacking direction LD.

  In addition, the force FA of the whole force detection apparatus 1, the force FB in the β axis direction, the force FC in the γ axis direction, the force FC in the γ axis direction, the rotational force MA around the α axis, the rotational force MB around the β axis, and the rotation around the γ axis. The force MC is calculated based on a signal proportional to the amount of charge accumulated from each charge output element 10. In this embodiment, four charge output elements 10 are provided. However, if at least three charge output elements 10 are provided, the rotational forces MA, MB, and MC can be calculated.

  As described above, according to the force detection device 1, the force detection device 1 can be reduced in weight by configuring the first member 22 and the third member 32 with the above-described low-density material.

  Further, the second member 24 and the fourth member 33 are made of the material having a large proof stress described above, whereby the strength of the second member 24 and the fourth member 33 can be increased. When the pressure is applied to the charge output element 10 by connecting and fixing 24 and the fourth member 33, deformation of the second member 24 and the fourth member 33 can be suppressed. Thereby, the detection accuracy of the force detection device 1 can be improved.

  Further, when the force detection device 1 is heated by configuring the second member 24 and the fourth member 33 with the above-described material having a small linear expansion coefficient, the second member 24 and the fourth member 33 are deformed by thermal expansion. The amount can be reduced, and an unnecessary force applied to the charge output element 10 can be suppressed. Thereby, the detection accuracy of the force detection device 1 can be improved.

  Further, when the first member 22 and the third member 32 are warped due to thermal expansion, the deformation amount of the first member 22 can be reduced in the portion of the through hole 20. The deformation amount of the three members 32 can be reduced. Further, the warp of the first member 22 is reduced by the through hole 20, and similarly, the warp of the third member 32 is reduced by the through hole 30. Thereby, it can suppress that unnecessary force is added to the charge output element 10, and the detection accuracy of the force detection apparatus 1 can be improved.

<Embodiment of single arm robot>
Next, based on FIG. 6, a single-arm robot which is an embodiment of the robot of the present invention will be described. Hereinafter, the present embodiment will be described with a focus on differences from the above-described embodiments, and description of similar matters will be omitted.

  FIG. 6 is a diagram showing an example of a single arm robot using the force detection device of the present invention. The single-arm robot 500 of FIG. 6 includes a base 510, an arm 520, an end effector 530 provided on the distal end side of the arm 520, and a force detection device 1 provided between the arm 520 and the end effector 530. Have In addition, as the force detection apparatus 1, the thing similar to each embodiment mentioned above is used.

  The base 510 has a function of accommodating an actuator (not shown) that generates power for rotating the arm 520, a control unit (not shown) that controls the actuator, and the like. The base 510 is fixed on, for example, a floor, a wall, a ceiling, or a movable carriage.

  The arm 520 includes a first arm element 521, a second arm element 522, a third arm element 523, a fourth arm element 524, and a fifth arm element 525, and rotates adjacent arms. It is configured by linking freely. The arm 520 is driven by being rotated or bent in a compound manner around the connecting portion of each arm element under the control of the control unit.

  The end effector 530 has a function of gripping an object. The end effector 530 has a first finger 531 and a second finger 532. After the end effector 530 reaches a predetermined operating position by driving the arm 520, the object can be gripped by adjusting the distance between the first finger 531 and the second finger 532.

  The end effector 530 is a hand here, but the present invention is not limited to this. Other examples of the end effector include, for example, a component inspection device, a component transport device, a component processing device, a component assembly device, and a measuring instrument. The same applies to the end effectors in other embodiments.

  The force detection device 1 has a function of detecting an external force applied to the end effector 530. By feeding back the force detected by the force detection device 1 to the control unit of the base 510, the single-arm robot 500 can perform more precise work. Further, the single arm robot 500 can detect contact of the end effector 530 with an obstacle or the like by the force detected by the force detection device 1. Therefore, an obstacle avoidance operation, an object damage avoidance operation, and the like, which are difficult with conventional position control, can be easily performed, and the single-arm robot 500 can perform work more safely.

  In the illustrated configuration, the arm 520 includes a total of five arm elements, but the present invention is not limited to this. When the arm 520 is constituted by one arm element, when constituted by 2 to 4 arm elements, and when constituted by 6 or more arm elements, it is within the scope of the present invention. .

<Embodiment of double-arm robot>
Next, a multi-arm robot which is an embodiment of the robot of the present invention will be described with reference to FIG. Hereinafter, the present embodiment will be described with a focus on differences from the above-described embodiments, and description of similar matters will be omitted.

  FIG. 7 is a diagram showing an example of a multi-arm robot using the force detection device of the present invention. 7 includes a base 610, a first arm 620, a second arm 630, a first end effector 640a provided on the distal end side of the first arm 620, a second arm 620, and a second end effector 640a. A second end effector 640b provided on the distal end side of the arm 630, and between the first arm 620 and the first end effector 640a and between the second arm 630 and the second end effector 640b. A force detection device 1 is provided. In addition, as the force detection apparatus 1, the thing similar to each embodiment mentioned above is used.

  The base 610 has a function of accommodating an actuator (not shown) that generates power for rotating the first arm 620 and the second arm 630, a control unit (not shown) that controls the actuator, and the like. Have. The base 610 is fixed on, for example, a floor, a wall, a ceiling, or a movable carriage.

  The 1st arm 620 is comprised by connecting the 1st arm element 621 and the 2nd arm element 622 so that rotation is possible. The second arm 630 is configured by rotatably connecting the first arm element 631 and the second arm element 632. The first arm 620 and the second arm 630 are driven by being complexly rotated or bent around the connecting portion of each arm element under the control of the control unit.

  The first and second end effectors 640a and 640b have a function of gripping an object. The first end effector 640a has a first finger 641a and a second finger 642a. The second end effector 640b has a first finger 641b and a second finger 642b. After the first end effector 640a reaches a predetermined operating position by driving the first arm 620, the object is grasped by adjusting the distance between the first finger 641a and the second finger 642a. Can do. Similarly, after the second end effector 640b reaches a predetermined operating position by driving the second arm 630, the distance between the first finger 641b and the second finger 642b is adjusted to thereby adjust the object. It can be gripped.

  The force detection device 1 has a function of detecting an external force applied to the first and second end effectors 640a and 640b. By feeding back the force detected by the force detection device 1 to the control unit of the base 610, the multi-arm robot 600 can perform the operation more precisely. The multi-arm robot 600 can detect contact of the first and second end effectors 640a and 640b with an obstacle by the force detected by the force detection device 1. Therefore, an obstacle avoidance operation, an object damage avoidance operation, and the like that have been difficult with conventional position control can be easily performed, and the multi-arm robot 600 can perform the operation more safely.

  In the illustrated configuration, there are a total of two arms, but the present invention is not limited to this. The case where the multi-arm robot 600 has three or more arms is also within the scope of the present invention.

  As mentioned above, although the force detection apparatus and robot of this invention were demonstrated based on embodiment of illustration, this invention is not limited to this, The structure of each part is the thing of arbitrary structures which have the same function Can be substituted. In addition, any other component may be added to the present invention.

  In the present invention, instead of the pressurizing bolt, for example, a device that does not have a function of applying a pressurization to the charge output element (piezoelectric element) may be used, and a fixing method other than the bolt is adopted. May be.

  In the present embodiment, the number of charge output elements is four. However, in the present invention, the number of charge output elements may be one, two, three, or five or more.

  In addition, the robot of the present invention is not limited to an arm type robot (robot arm) as long as it has an arm, but is another type of robot such as a scalar robot, a legged walking (running) robot, or the like. Also good.

  The force detection device of the present invention is not limited to a robot, but other devices, for example, a transport device such as an electronic component transport device, an inspection device such as an electronic component inspection device, a component processing device, a moving body, a vibrometer, an acceleration It can also be applied to measuring devices such as gauges, gravimeters, dynamometers, seismometers, inclinometers, and input devices.

DESCRIPTION OF SYMBOLS 1 ... Force detector 2 ... 1st base 20 ... Through-hole 22 ... 1st member 23 ... Convex part 221 ... Lower surface (1st surface)
231 ... Top surface 24 ... Second member 241 ... Female screw 271 ... Center shaft 272 ... Center 3 ... Second base 30 ... Through hole 32 ... Third member 33 ... Fourth member 321 ... Upper surface (second surface)
331 ... Inner wall surface 4 ... Analog circuit board 41 ... Hole 43 ... Pipe 5 ... Digital circuit board 50 ... Through hole 6, 6A, 6B, 6C, 6D ... Sensor device (pressure detector)
60 ... Package (container)
71 ... Pressurized bolt 10 ... Charge output element (piezoelectric element)
DESCRIPTION OF SYMBOLS 11 ... Ground electrode layer 12 ... 1st sensor 121 ... 1st piezoelectric material layer 122 ... Output electrode layer 123 ... 2nd piezoelectric material layer 13 ... 2nd sensor 131 ... 3rd piezoelectric material layer 132 ... Output electrode Layer 133 ... Fourth piezoelectric layer 14 ... Third sensor 141 ... Fifth piezoelectric layer 142 ... Output electrode layer 143 ... Sixth piezoelectric layer 151, 152, 153 ... Wiring 16 ... Side wall portion 161 ... Tube Shape part 162 ... Flange 171, 172, 173, 174 ... Screw 500 ... Single arm robot 510 ... Base 520 ... Arm 521 ... First arm element 522 ... Second arm element 523 ... Third arm element 524 ... First 4th arm element 525 ... 5th arm element 530 ... End effector 531 ... 1st finger 532 ... 2nd finger 600 ... Multi-arm robot 610 ... Base 620 ... 1st arm 621 ... first arm element 622 ... second arm element 630 ... second arm 631 ... first arm element 632 ... second arm element 640a ... first end effector 641a ... first finger 642a ... Second finger 640b ... second end effector 641b ... first finger 642b ... second finger LD ... stacking direction SD ... clamping direction NL1, NL2 ... normal Qx, Qy, Qz ... charge

Claims (13)

A first member;
A second member coupled to the first member;
A piezoelectric element coupled to the second member,
The material which comprises the said 1st member differs from the material which comprises the said 2nd member, The force detection apparatus characterized by the above-mentioned. The first member has a plate shape,
The piezoelectric element and the second member are disposed at an end portion of the first member,
The force detection device according to claim 1, wherein a through hole is formed in a central portion of the first member. A third member;
A fourth member coupled to the third member and sandwiching the piezoelectric element with the second member;
The material which comprises the said 3rd member is a force detection apparatus of Claim 1 or 2 different from the material which comprises the said 4th member. The third member has a plate shape,
The piezoelectric element and the fourth member are disposed at an end of the third member,
The force detection device according to claim 3, wherein a through hole is formed in a central portion of the third member.   5. The force detection device according to claim 3, wherein a material constituting the second member is the same as a material constituting the fourth member.   The force detection device according to any one of claims 3 to 5, wherein a material constituting the first member is the same as a material constituting the third member.   The force detection device according to any one of claims 3 to 6, wherein a density of a material constituting the third member is smaller than a density of a material constituting the fourth member.   The force detection device according to any one of claims 3 to 7, wherein a proof stress of a material forming the fourth member is larger than a proof stress of a material forming the third member.   9. The force detection device according to claim 3, wherein a linear expansion coefficient of a material constituting the fourth member is smaller than a linear expansion coefficient of a material constituting the third member.   The force detection device according to any one of claims 1 to 9, wherein a density of a material constituting the first member is smaller than a density of a material constituting the second member.   The force detection device according to any one of claims 1 to 10, wherein a proof stress of a material constituting the second member is larger than a proof stress of a material constituting the first member.   The force detection device according to any one of claims 1 to 11, wherein a linear expansion coefficient of a material constituting the second member is smaller than a linear expansion coefficient of a material constituting the first member. Arm,
An end effector provided on the arm;
A force detection device that is provided between the arm and the end effector and detects an external force applied to the end effector;
The force detection device includes a first member,
A second member coupled to the first member;
A piezoelectric element coupled to the second member,
The material constituting the first member is different from the material constituting the second member.

Images